The present invention relates to a method for providing road users with information and to a device for carrying out the method.
One of the main objects of current resource work has been to provide road users, in particular motor vehicles, with up to date information on traffic problems and dangerous situations in road traffic which are also caused by motor vehicles.
German publication DE 197 49 978 A1 discloses a method for informing a traffic control center about the distance traveled by a vehicle with a terminal in a road network, local data representing the respective location of the terminal being sensed repeatedly by a location determining device. Reference points are defined at a plurality of locations on the route traveled on the basis of criteria present in the terminal, the reference information which relates to these reference points being transmitted from the terminal to the traffic control center.
The sensing of the route of a vehicle is suitable for detecting vehicles traveling in the wrong direction and for acquiring geographical traffic information. The latter information can be used by a control center to assign traffic data, for example vehicle speed and travel time, to locations on the vehicle's route, that is to say to locations in a digital map of the road network, traffic state messages, traffic messages and navigation aids being generated in the control center on the basis of traffic data of a plurality of vehicles.
One object of the invention is the object of specifying a method for providing road users with information on a dangerous situation, which method makes it possible for road users to have a rapid, direct and detailed overview of the location or the region of the dangerous situation. Another object of the invention is to provide a device for carrying out the method.
In one method for providing road users with information about a route section traveled along by a motor vehicle before a dangerous situation, the position and the direction of travel of the motor vehicle are sensed repeatedly as measured values along the route section in a suitable sensor system in the motor vehicle. The measured values of the sensor system are stored as route points if the angular difference, weighted with the distance traveled along since the route point last stored, between the current direction of travel and the direction of travel at the route point last stored exceeds a predefined threshold value. In addition, a route point is stored when a warning function in the motor vehicle is activated in the dangerous situation. The position of at least one stored route point and the current position of the motor vehicle are passed on in a warning message to the road users in a limited surrounding area.
As a result of the transmission of positions which have just been traveled through during or before a dangerous situation, linked to a warning, other motor vehicles which are located in the surroundings are made aware of a source of danger, for example of a motor vehicle which is stationary on the road way or of a vehicle which is approaching a traffic jam. The weighting of the angular difference with the distance traveled, that is to say linking of a length measurement to an angular value, ensures that reference points are generated even in bends with very tight radii of curvature. For example, it is thus possible even to sense a motor vehicle which turns around on a road and travels in the opposite direction on the same carriageway, either intentionally or as a result of compulsion. The information content and thus the local resolution of the warning message is increased or improved significantly with respect to the methods known from the prior art. The road users receive their information on dangerous situations and their origins directly from the motor vehicle which is causing the danger or from the motor vehicle which is threatened by the danger. The fastest possible communication is provided. The method is particularly suitable for application on high speed roads and/or freeways.
Preferably the following is true|ΔφΔs|>1.0*10−1 deg2,Δs being the distance traveled since the route point last stored, Δφ being the angular difference between the current direction of travel and the direction of travel at the route point last stored and 1.0*10−1 deg2 being the threshold value. The order of magnitude of the threshold value has proven particularly favorable in practice. As a result, a route point is generally set even in tight bends. Optimum resolution of the route section profile is ensured.
In particular, two successive route points can be a predefined minimum distance apart. This criterion avoids an excessively large number of route points which are not required to determine and reproduce the route section which is actually being traveled along.
In a further refinement of the invention, the distance between two successive route points lies below an upper threshold value in the respective longitude and latitude. All the distance information is given in geographic units, which avoids additional conversion steps in the algorithm of the execution of the program.
The driver preferably activates the warning function. As a result of automatic activation, the user of the motor vehicle can freely decide whether he sees his vehicle as a risk for other road users in the given situation. However, activation can also take place automatically as a function of a vehicle parameter. For example a hazard warning light may be provided as the warning function.
In particular, the road user can decide on the relevance of the dangerous situation for his own further course of travel by means of the received positions over the route section traveled along by the motor vehicle. The road user checks the route section of the vehicle outputting the warning message for correspondence with at least part of his route section last traveled along. The road user does not require a digital road map for this relevance check. He can use simple, known arithmetic methods to decide whether he is located on the road or lane with the expected obstacle.
In a further refinement of the invention, the road user also checks the route section of the motor vehicle for correspondence with at least part of his course of travel which is still to be traveled along. This requires the road user to be capable of using his own navigation system and digital road map to acquire data on at least part of his future course of travel and check this data for correspondence with the route section of the vehicle.
One way of achieving the second object mentioned is by way of a device for carrying out the method mentioned in which a navigation system is provided as sensor system for repeatedly sensing the position and the direction of travel of the motor vehicle.
The navigation system may be a GPS receiver.
Further advantageous refinements of the invention are apparent from the dependent claims.
The invention will be explained in more detail by means of a plurality of exemplary embodiments in the figures. Other objects, advantages and novel features of the present invention will also become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.